Liquid phase extraction of glyceride oils and acids



Patented July 28, 1942 ICE LIQUID PHASE EXTRACTION F GLYCERIDE OILS ANDACIDS Stephen E. Freeman, Wauwatosa, Wis assignor to Pittsburgh" PlateGlass Company, Allegheny County, 2a., a corporation of Pennsylvania NoDrawing.

Original application January 17,

1939, Serial No. 251,340. Divided and this application August 15, 1941,Serial No. 407,001

3 Claims. '(01. 260-428) The present invention relates to the treatmentof fat and oils, of the glycerlde type, and it has particular relationto the treatment of glyceride oils such as linseed oil, oiticica oil,tung oil, soy-bean oil, cottonseed oil, hempseed oil, fish oil, tallowand similar oils which are employed as film-forming constituents inpaints, varnish, enamels, synthetic resins, and as food products, drugproducts and in soaps, plastics, etc.

One object of the invention is to separate an oil of the glyceride typeintovarious fractions each or most of which will have greater value thanthe original oil when the fraction is suitably selected for use inpaints, synthetic resins, food products, plastics, soaps, etc.

For example, the invention provides a simple and convenient method ofseparating oils comprising mixtures of glycerides of fatty acids ofdifferent degrees or types of unsaturation into fractions certain ofwhich contain a higher ratio of the more unsaturated or more activelyunsaturated components than the original mixture.

A second object of the invention is to provide a method of extractingsuch glyceride oils as linseed, soy-bean, cottonseed fish oil, train oiland similar oils from pulps or means containing them, while leaving mostof the phosphatides in areadily removable form in the meal.

A third object of the invention involves the provision of a simple andconvenient method of separating mixtures of saturated and unsaturatedfree fatty acids into fractions, one of which is relatively moresaturated than the other.

These and other objects will be apparent from consideration of thefollowing specification and the appended claims.

Oils of the glyceride type such as areemployed in the preparation offoods, soaps, or as filmforming ingredients in many paints, varnishesand enamels are found in certain plants or in the seeds thereof, and asfatty constituents in the bodies of animals and fish, and areessentially different from petroleum or mineral oil, since they arecomposed mainly of mixtures of the glycerides of the fatty acids such asstearic, palmitic, oleic, linoleic, clupanodonic, linolenic, licanic,elaeostearic, and many others.

tionship in which they are extremely active, and

The number and type of glycerides present will vary, depending upon thespecific oil. The general or type structure of these g yce d s may berepresented by the formula:

I: HORl H OR) H OR:

and are monodi or tri glycerides according to the number of acyl groupsin positions 121.3: and Rs which have been introduced by esteriflcationof the glycerol with a fatty acid.

The principal difference between these glycerides, aside from variationsin the number of ester groups, consists in variation in the length of ithe carbon chains, and in the number and arrangement of the double bondsin the alkyl groups or residues. For example, palmitic acid of theformula 0 onucnnuo contains 16 carbon atoms while stearic acid contalus18 carbon atoms. The formula of stearic acid is CHJ(GHZ)16C Both arefree of double bond and ar non-drying. Oleic acid of the probableformula cm (one) 1CH:CH(CH2) qcoou HH HHHHHHH H H 1817161514131211109 87 (Y5 4 3 2 1 Elaeostearic acid and licani'c acid, glycerides of whichoccur in tung oil and oiticica oil respec-'- tively contain doublebonds-in conjugate relatheir glycerides dry faster than any of theforegoing. i

Elaeostearic acid acid) is of th formula:

nnnnnnnnnnnnnnnnrr o n0-0-0 c-c=o-c=c-c=o-c-c-o-o-c c-c-ofim rrnnnnnnnnnn 181716151413121110 o s 1 e 5 4 s 2 1 These glyceride oil arecustomarily extracted from the seed meals or other material containingthem by application of high pressure, or by extraction with a suitableorganic solvent, such as (9,11,13 octadecatn'enoic hexane. Both of thesemethods are objectionable for numerous reasons. For example, if pressingis resorted to, the removal of oil is incomplete and in event thepercentage of oil in the meal or pulp is initially low, the unextractedoil may constitute a very large percentage of the total. Extraction bymeans of organic solvents,

such as hexane involves a very high explosion hazard, and violentexplosions often resulting in loss of life are not uncommon in plantemploying such process. Both processes are objectional because ofnon-selectivity. For example, in either the pressing operation or thesolvent extraction with a hydrocarbon solvent 0.5 to 1% phosphatides, 1or 2% free fatty acids are obtained in the extracted oils. Non-dryingconstituents such as relatively highly saturated glycerides are alsoremoved in the oil. time certain materials which seem to exert ananti-oxidantleffect upon the drying oils are obtained in the mixture.

Most of the components of the natural oils and the substances (meals orthe like) containing the oils are of themselves of substantial value forvariouspurposes. For example, the pulps are valuable as cattle foods,the more highly unsaturated glyceri'des or the glyceridcs containingconjugate double bonds, which are more highly active than the moresaturated glycerides, are useful as film-forming constituents in paints,varnishes, and lacquers. They are also useful as modifiers in resins.The saturated glycerides and the hydrogenatedor unhydrogenatedglycerides of a low degree of saturation are useful in foods and thelike. The free acids of all types are useful in the preparation ofresins, plastics and soaps and other important applications. Thephosphatldes are of value in foods, pharmaceutical preparations and asemulsifying agents, etc.

It is the object of refining processes for such oils to remove at leasta part of certain of the constituents which for specific purposes areobjectionable. For the paint and varnish industries it is particularlydesirable to remove those portions which cause so-called break or sludgeformation upon heating, and to remove'excess free fatty acids, color andnondrying portions. The conventional method of refining these oilsinvolves the application either of strong sulphuric acid which chars andcoagulates the by-product portions, or treatment with sodium hydroxide.Both of these methods are drastic in their action upon the oildestroying some portions entirely, thus producing a by-product which haslittle or no value. In addition to causing destruction or degradation ofthe by-products, such treatment also tends to decompose a part of thedrying, or film-forming glycerides. The methods are tedious and requireconsiderable equipment and much space for storage purposes. Furthermore,the reagents employed in the process are not recoverable and along withthe by-products which are obtained in a degraded form constitute aconsiderable source of loss.

The present invention involves as one feature the discovery that certaintypes of non-reactive organic polar solvents notably those which, at lowtemperatures, are not completely miscible with glyceride oils, may byproper control of temperature be employed preferentially to dissolveunsaturated or more actively unsaturated components of glyceride oilseither from simple or crude mixtures of the glycerides, or frommaterials such as seed meals or pulps containing At the same theglycerides. Accordingly, by'treating the oils,

, or materials, such as seed meals or pulps containlog the oils, withone or more of the selective solvents at a temperature sufficiently lowto obviate complete solution of the oil and at a temperature high enoughfor the solvent to be liquid, it becomes possible to separate themixture into two liquid components, onecomprising the solvent saturatedwith'a fraction rich in unsaturates, the second consisting of glycerideswhich are relatively poor in unsaturates.

These liquids contain activating groups, which usually are polar andwhich may be selected from a relatively large class among which mayable. In general, there must be at least one activating or polarizinggroup for every four carbon atoms and in many cases the ratio of thegroups must be substantially increased.

The permissible number of carbon atoms in the molecule of the solventfor each activating group may be tabulated as follows:

TABLE A Permissible Activating group $8352 5 -on .l 3

o 0 OH 2 ing power, e. g.

In most cases the applicability of a particular solvent for thefractionation; of glyceride oils can be determined from the above tablein which the permissible carbon atoms for each offlthe more common ofthe polar or activating groups are listed. In order to determine ifaparticular solvent is applicable, the number of permissible carbonatoms for all of the activating groups are added together. If the sum isequal to or greater than the number of carbon atoms actually present inthe nucleus of the solvent molecule, the latter can usually be employedselectively to dissolve unsaturated glycerides from more saturatedglycerides. The operation of the rule is illustrated by furfural H--(l(i-CH CHO \ The latter contains two double bond (C==C) groups, oneoxy linkage and an aldehyde The sum of permissible carbon atoms forthese groups is 1+1+1+2 or 5, which exactly correspondsto the number ofcarbon atoms in the furfural nucleus.

In the cases of groups having but low activatetc., it is usuallynecessary that an additional and more active group be included in themolecule. However, the groups of low activating power then increase theselective action of the molecule for unsaturates. This is also true withthe halogens, such as chlorine and bromine.

It will be apparent that most of the solvents, if sufllciently heated,will become miscible with all components of the oil. Accordingly, thetemperature must be sufliciently low and ratio-of the solvent must bemaintained in a region where solution is incomplete. Usually, the lowerthe temperature of treatment (within reasonable limits) the moreselective will be the solvent and the higher will be the proportion ofthe unsaturates in the fraction dissolved. However, the proportion ofthe glycerides recovered in the dissolved fraction is also decreased.Therefore, in commercial operation it is preferred to compromise betweenextreme selectivity and high yields, and to employ the solvent at suchtemperature .and in such proportion that two fractions separate but thata reasonable yield is obtained in the dissolved fraction.

In the practice of the invention, it is preferred to treat the oilscontaining saturated and unsaturated glycerides at thetemperature and'ina ratio at which separation into fractions occurs. The treatment of oilor meal may be by batch, or multistage, or counter-current or concurrentflow, or by combination of these methods.

In the application of the process to meals or pulp in order to removethe oil therefrom, the material to be treated containing an oil, e.v g.soy-bean oil, or linseed oil, or marine oil, or the like may be treatedat a temperature sufficient to dissolve all'or a substantial proportionof the oil therein. The liquids are separated from the oil must not betoo low because an undue prosolids and the temperature is adjusted toobtain separation into two liquid phases, one-oi which is rich inrelatively saturated glycerides and contains a small amount of solventand the second consists of solvent in which is dissolved a fraction richin unsaturates. The ratio of solvent to portion of it will be dissolvedin the more saturated fraction and there will not then be sufllcientamount satisfactorily to dissolve and separate the more unsaturatedfraction. Conversely, if too much solvent is employed an excessiveamount of saturates'will be taken into solution and fractionation cannotbe accomplished. Probably in most instances the solvent should be withina range of two to twelve parts by volume of solvent to one part of oil.In batch extrac tions, a ratio of about four parts of solvent to i onepart of oil has been found to be a good average. Mechanical separationof the two fractions by settling and decantation, or by centrifugation'may be easily effected. The solvent can be recovered by steamdistillation or by crystallization or by the additionof a non-solventfor the oil I such as water, in order to cause an alteration of thecharacteristics of the solvent, etc.

A series of tests was conducted upon soy-bean oil having an iodinenumber of 136, the solvents were employed in the ratio of four parts toone part of oil. In the event liquid separation did not occur at roomtemperature the mixtures were chilled. The chilling was continued untilseparation of two liquid fractions occurred, or if no separation tookplace, to a temperature of 20 C. The solvents tested are listed in thefollowing table. In the event that solidification of one or morecomponents of the mixture occurred before liquid separation took placethe mixture was recorded as miscible. The third column in which thenumber of carbon atoms in the molecule is listed in the column and themaximum number of carbon atoms theoretically permissible as calculatedby assignment of numbers from Table A to the activating groups areincluded in the last column.

Those solvents capable of separating the oil into two fractions aredesignated as I. Those which do not so separate are designated as M.

TABLE B Carbon atoms Miscibility at -20 C. or above Calculated SolventIn the molecule - Capryl alcohol..

Cyclohexyl alcohoL Ethylene glycol. Propylene glycol- HHgr-(HHHHi-(HHggggggggi-(HHH qmqcmmmuw wuzocaocucncnwsmu oamwt-i Similarlycottonseed oil may be extracted with a quantity (four volume, more orless) of active solvents such as:

Eth lidene diacetate i 1 alcohol n prop? 'Met yl levulinate Iso roolalcohol ctnte and many others to obtain immiscible systems thatseparate into two phases which can be separated by decantation or othermethods. V

Most of these solvents will also behave simi larly with fish oil,linseed oil, tung oil, olive oil and animal fats such as tallow.

In a series of quantitative tests to determine the selectivity ofcertain liquids for unsaturated components of a glyceride oil, asoy-bean oil having an iodine number of 136 was treated with liquids inthe ratio of 1 part of oil. to 4 parts of extracting liquid. Extractionwas efiected by agitating together the oil and the extracting agent atthe temperatures indicated in the following table. They weresubsequently allowed to separate into two layers. One layer consisted ofoil relatively poor in uns'aturates in which was dissolved some of thesolvent. The other layer comprised a solvent in which was dissolved oilrich in unsaturates. The layers were then separated and the extractingagent was eliminated by vacuum distillation. Iodine numbers weredetermined by the Wijs method. The results are tabulated below:

TABLE C Temp. Percent Iodine number Difier- Solvent se aratl on, Ex-Rafli- Ex- Rafli- C. tract nate tract note Nitroethane 0 28. 3 71. 7148. 2 130. 3 17. Methyl formats 0 13. 8 86.2 149. 6 133. 8 15. 12 28.571. 7 144. 2 132. 9 11. Methyl cellosolve- 28 9. 0 91 147. 0 132. 2 14.70 43. 0 57 138. 0 131. 6. Methyl levulinate 27 15 85 147. 0 132. 5 14.Proplonitriie- 0 33. 2 66. 8 145. 5 131. 2 l4. Furiural... 27 28 72 146.0 132. 0 14. 40 38 62 144. 5 131. 0 13. Trimethyl phosphat 70 2 90 147.0134. 0 13. 128 ll 89 144. 0 132. 8 11. Acetaldehyde 0 27. 9 72. 1 144. 3131. 9 12. Triethyl phosphate 0 41 59 142. 1 130. 0 12. Acetonyiacetone. 2'! 80 146. 0 134. 0 12. 50 47 53 141. 0 131. 0 10. Acetone (3%wete 27 41 59 139. 6 I32. 8 6. Diace yl... 0 18 82 145. 0 133. 2 11.Nitromethane.. 27 6 94 145. 0 133. 5 11.

95 14. 3 85. 7 143. 0 134. 5 8. Glycol diacetate. 65 38 62 141. 0 129. 711. 50 23 77 141. 0 132. 0 9. Ethyl oxalato 0 55. 8 44. 2 140. 3 129. 211. Methyl cellosolve 0 41 59 140. 2 130. 2 10. 70 23. 3 76. 7 139. 5131. 7 9. 27 56 44 138. 5 130. 2 8. 0 56.5 43.5 138.8 130.7 8. Ethylmaleate 0 26 74 140. 1 132. 0 8. Acetic anhydride. 90 51 49 138. 2 131.0 7. Carbitol. 125 22 5 77. 5 139. 0 132. 8 6. Propylene glycOL 27 5 95139. 0 135. 0 4. Acetic acid 50 62 38 137. 8 133. 8 4. Methyl hutano- 049 51 137. 0 132. 2 3. n-Bnty'ramide.-- 1%) 70 136. 2 132. 5 3.l'sotgropnnol 28 9 91 138.0 135. 0 3. E yl glycolate-.- 77 21 77 138. 0135. 0 3.

Linseed oil was similarly extracted with acetic acid with the followingresults:

Iodine number Marine oil (menhaden) was extracted with a series ofsolvents-as follows:

Iodine number Solvent 1 Original 321%; 3;"

Methyl eellosolve Q. 187. 5 208 182 Ethyl acetoacetate and phenol 186201 161 Ethyl acetoacetate 186 281 161 Phenol and petroleum ether 184189 181 Furfural 184 206 157 In the example in which ethyl acetoacetateand phenol were employed in admixture, the ratio of the two was ethylacetoacetate-80 parts, phenol 20 parts.

Where phenol and petroleum ether were employed the ratios of the twoingredients were Indices of refraction Extraction agent g SolubleInsoluble Ethylene chlorohydrin. l. 4820 1. 4869 1. 4809 Pyridine 1.4320 1. 4850 l 1. 4810 These solvents indicated by the letter M in TableB could not be used by themselves to effect fractionation of highlyunsaturated glycerides from less highly unsaturated ones, because ofundue miscibility with both types. However, in many cases it is possibleto mix the active solvent with an aliphatic hydrocarbon such as hexane,butane, propane, dodecane, or the like, which is relatively immisciblewith the selective solvent. The hydrocarbons tend to pull the saturatedglycerides away from the active solvent and permits separation of theoil into two fractions. The ratio of hydrocarbon to active solvent mayvary over a broad range, e. g. 1 to 10 parts of hydrocarbon per 1 art ofthe active solvent. However, good results have been obtained byemployment of a ratio of 4 to 1. In general the greater the proportionof hydrocarbon employed, the stronger will be the tendency to pull awaythe saturated glycerides from the polar solvent.

Similar methods may be employed to efiect fractionation of mixtures ofsaturated and unsaturated fatty acids. These are usually solubleessentially of active solvent which is rich in unsaturated acids and theother consisting essentially of hydrocarbon which is-rich in saturatedacids. This process is illustrated by acids fro linseed oil: I

. Parts by volume Linseed oil acids 200 Petroleum ether (B. P. 3060 C.)200 Anhydrous furfural 400 These were agitated together at roomtemperature and allowed to separate into layers. The solvents were thendistilled off from the two fractions separately under vacuum.

Iodine value of original acid 173 Iodine value of acid in hydrocarbon166 Iodine value of acid in furfural 193 A 30 per cent mixture oflinseed oil fatty acids in the same hydrocarbon was agitated with 1volume of furfuryl alcohol and separated into fractions at roomtemperature.

Iodine value of original acid 173 Iodine value of acid in hydrocarbon162 Iodine value of acid in solvent 203 Ethylene glycol diacetate wasagitated at room temperature with a 12 per cent by volume mixture oflinseedoil fatty acids in petroleum ether, and the mixture was separatedinto fractions from which the solvents were eliminated.

Iodine value of original acids 173 Iodine value of acids in hydrocarbon168 Iodine value of acids in solvent 175 Where the herein-describedselective polar solvents are employed to extract glyceride oils,

and free fatty acids from seed meals, extraction preferably is effectedunder conditions such that all components pass into solution. Thedissolved material may then be suitably fractionated by manipulation oftemperatures or by modification of the solubility characteristics byaddition of hexane or the like. Subsequently the dis- An extension ofthe foregoing method would involve treatment of mixed fatty glycerides,e. g. linseed oil or soy-bean oil with a selective polar solvent such asiurfural or ethyl acetoacetate or the like, to obtain two liquid phases.The phase comprising the solvent and the more unsaturated glyceridescould then be treated by batch or by counter-current or concurrentextraction with hexane or other hydrocarbon to pull out additionalsaturated glycerides, thus leaving a higher concentration of unsaturatesin the fraction obtained from the solvent.

The immiscible fraction of oil containing a more fully saturatedglyceride after separation from the solvent may be treated in anadditional stage with a more sharply selective solvent to removetherefrom additional unsaturated material.

An example of such procedure would involve initial extraction ofsoy-bean or similar oil with furfural followed by treatment of theimmiscible phase with nitroethane to remove therefrom an additionalquantity of unsaturated material.

Similarly polar solvents such as methyl cellosolve acetate which aremiscible at all practicable temperatures with glycerides such as occurin 75 over a broad range.

tung oil and oiticica oil may be employed in combination with hexane orother open chain hydrocarbons to obtain separation into a hydrocarbonsoluble fraction and a fraction soluble in the polar or active solvent.'In this process the proportion of hydrocarbon to the polar solvent mayvary ratio of hydrocarbon the more selective will be the system.

In some cases where extreme selectivity of the system is not required, areadily miscible solvent such as phenol may be incorporated with a moreselective solvent to increase yield of extract.

Such system is illustrated by ethyl acetoacetatephenol above described.These ingredients may be employed in a ratio of 1 part of phenol to 4parts of ethyl acetoacetate.

Separation of the glyceride or acid fractions 7 and the solvents may beeflected, as previously stated, by crystallization, vacuum distillation,steam distillation or other methods. A convenient method involvesaddition .of water, which tends to reduce the, solubility of theglycerides in the solvent. The water may be employed in an amountsumcient to saturate the solvent or if the solubility of water in thesolvent is high it may be added until the glycerides or the free fattyacids separate.

Appropriate variations in the mode of manipulating the fractionsobtained by solvent extrac-; tion of glyceride oil would involve furtherfractionating or splitting one ofjthe fractions, e. g-

the solution of highly unsaturated glycerides, to obtain a portion whichis richer in unsaturates than the initial fraction and a fraction whichis poorer in unsaturates. The. latter fraction can then be recycled byadmixing it with fresh glycerides or with glycerides at an appropriatestage of extraction. For example, a fraction comprising furfuralsaturated with gLvcerldes of high drying power may be steam distilled todrive off some of the solvent, or may be chilled, thus causing some ofthe less soluble (more saturated) glycerides to be separated. Thislatter fraction can then be recycled.

Manifestly, the highly miscible solvents which can not be convenientlyemployed by themselves in the fractionation of mixed glycerides canstillbe employed to extract the glycerides from seed meals and pulp.Afterwards the more selective solvents can be applied to the whole oilafter or before elimination of the initial solvent to separate a highlyunsaturated fraction. Ethyl acetoacetate is of particular value in theextraction of fish oils.

It possesses low solvent powers for the break and color constituents ofvarious oils and accordingly by application of it, it is possibledirectly to dissolve out most of the constituents of the oil, useful inpaints and varnishes, to obtain a product which is low in break andcolor and which dries rapidly to non-tacky films. When warm, it may alsobe used directly'to extract vegetable oils such as linseed oil, orsoy-bean oil from the meal or pulp. The following constitutes a specificexample of its application to the treatment of raw fish oil, such assardine or menhaden oils.

Oil in the ratio of one part was contacted in, three steps with threeparts of ethyl acetoacetate at room temperature, to obtain a fraction insolution constituting 60 per cent of the total volume of oil. Thisfraction upon separation from the solvent by evaporation of the solvent,or by adding water was found to be of a pale green color However. .thehigher the not show any and to dry practically free of tack. Thefish-like odor was substantially less pronounced than in ordinary oil.The residue was of a deep reddish brown color or substantially lowerindex of refraction and iodine number than the original oil. It driedvery slowly and remained permanently tacky. The yield of oil can beincreased though with slight impairment of quality by the addition ofphenol in considerable portions to 30 per cent more or less). The use ofmethyl alcohol or ethyl alcohol in 2:1 ratio on the ethyl acetoacetateextract of the raw fish oil produced a ramnate whose acid number was 0.0and whose iodine number had increased to the remarkable value of 212.5.This oil was pale green; it had a very bright appearance. The dryingtest showedthe film to be slightly better than raw linseed oil in regardto tack. The test values are as follows: I

Iodine value Oil (Wm) Acid value 186 15.3 let extract 201 7. 7 Alcoholtreated 212. a o. 0

Combination of ethyl acetoacetate and furfural extraction may sometimesbe desirable. For example, raw fish oil (such as menhaden) was extractedwith ethyl acetoacetate at 39 C. and a fraction containing 80% of theoil was recovered. The product was then extracted with furfuralsaturated with water in 1:1 ratio, at C. The loss from the product as aresult of extraction was only 2 or 3%. and the color was materiallyimproved. The results of tests conducted upon the material are tabulatedas follows:

Oil Acid value Raw marine 15. 3 80% extract 5. 6 Furfural-HaQ extractedoil 0. 9

Marine oils,. which normally produce tacky films when treated withsolvents, in accordance with the provisions of the present invention, dobreak even when heated to upward of 600 F. They dry faster than linseedoil. The

films produced by them are non-tacky, free of fishy odor and are highlyresistant to blistering.

Upon extracting linseed oil with 2 to 3 parts by weight of ethylacetoacetate, 80% of the oil was dissolved and upon recovery from thesolvent it was found to be free from break and of a pale yellow colorwhich changed to green when the oil was heated to 600 F.

Other drying oils such as hempseed oil, soybean oil, perllla oil, etc.,may be treated with January 17, 1939, now issued as Patent No.2,200,391. I

Reference is also made to the following copending applications, whichare continuations of the foregoing patents:

Ser. No. 334,997, filed May 13, 1940. Ser. No. 335,000, filed May 13,1940. Ser. No. 334,998, filed May 13, 1940. Ser. No. 335,002, filed May13, 1940. Ser. No. 335,003, filed May 13, 1940. Ser. No. 334,999, filedMay 13, 1940. Ser. No. 335,005, filed May 13, 1940.

group is selected from the class consisting of ni-.

tro amido and amino, which solvent at a low temperature is relativelyimmiscible with the saturated glycerides, but being completely miscibleat elevated temperatures, the temperature of treatment being above aboutminus 20 C., the

ratio of solvent and the temperature being below that of completemiscibility with the glycerides, separating the two resultant phaseswhile they are both in liquid state, one containing primarilyundissolved glycerides relatively poor in unsaturated glycerides andcontaining some solvent and the other consisting of solvent in which isdissolved glycerides relativelyrich in unsaturates.

'2. A process of selectively separating a fraction which is rich inunsaturated glycerides from a material containing said glycerides inadmixture with a more completely saturated glyceride,

which process comprises contacting the material with an organic polarsolvent, the solvent being selected from a class consisting of formamid,

- acetamide, propionamide, butyramide, orthonitroanisole, diethylenetriamine, triethylene tetraamine, amiline, ethyl n-methyl carbamate,diethylamino ethanol, said solvent at a low temperature being relativelyimmiscible with the saturated glycerides, the temperature of treatmentbeing above about minus 20 0., the ratio of solvent and the temperaturebeing below that of complete miscibility with the glycerides, separatingthe two phases while they are both in liquid state, one containingprimarily erides relatively poor in unsaturates and vcontaining somesolvent and the solvent in which is dissolved glycerides relatively richin unsaturates.

3. A process of selectively separating a fraction rich in glycerides ofrelatively short chain length furfural, ethyl acetoacetate, or the like,in order to obtain refined fractions, if so desired.

Detailed discussion of the treatment of glyceride oils with furfural arecontained in copending application Serial No. 144,315, to Stephen E.

from a glyceride oil containing them, in admixture with glycerides ofrelativelylong chain length, which process comprises contacting. the

1 oil with an organic polar solvent containing as Freeman, filed May 22,1937, now issued as Patent No. 2,200,390 of which continuation in part.1

The foregoing examples are to be considered merely as illustrative andnumerous modifications may be made therein without. departure thepresent case is a from the spirit of the invention or the scope of thefollowing claims.

The present application is a copending application Serial No.

division of [my 251,340, filed a polarizing group one of the classconsisting of amino and amido, which solvent at low temperatures isrelatively immiscible with the long chain glycerides, the conditions ofcontacting the glyceride and solvent being such that the system remainsliquid and the glycerides are incompletely dissolved, separating the tworesultant liquid phases and removing the solvent phase to obtain saiddesired fraction.

S'I'EPHENH-EL,

undissolved glyc-- other consisting of

